Hypodermic injector with safely held release means



Feb. 13, 1968 SJ SARNOFF ET AL 3,368,559

HYPODERMIC INJECTOR WITH SAFELY HELD RELEASE MEANS Filed Sept. 17, 1965QM N INVENTORJE Stanley J. Sarnoff 4 1 Geo/ye B. Gal/ ins BY WM MATTORNEYS Patented Feb. 13, 1968 3,368,559 HYPODERMIC INJECTOR WITHSAFELY HELD RELEASE MEANS Stanley J. Sarnoff, 7507 Hampd'en Lane 20014,and

George B. Calkins, 6806 Selkirk Drive 20034, both of Bethesda, Md.

' Filed Sept. 17, 1965, Ser; No. 488,055

8 Claims. (Cl. 128218) This invention is directed to improvements overthe hypodermic syringe disclosed in the patent to Stanley J. Sarnoff etal., 2,832,339, granted Apr. 29, 1958.

In particular, the invention relates to improvements in the releasemechanism of the hypodermic syringe disclosed and claimed in thatpatent.

One type of hypodermic syringe comprises a hypodermic injector which canbe carried on the person of the user with the needle thereof in asheathed condition, the device being quickly and easily releasable byremoving a safety pin and pressing a tube holding a medicament vialagainst the portion of the body which is to receive the medicament,while grasping an outer sleeve, the relative movement of sleeve and tubecausing the needle to automatically move rapidly outwardly from the tubeunder the influence of a spring and the medicament in the vial to beejected through the needle. This spring is normally retained undercompression by a detent within the device.

It is possible, in the prior art devices including the device on whichthis is an improvement, to inadvertently cause ejection of the needleand ejection of medication after the safety pin has been removed,without relative sleeve and tube movement, this occurring, for example,by reason of rough handling or dropping of the syringe.

It is an object of this invention to provide improved detent means tominimize thechances of inadvertent release of the spring .withconsequent inadvertent ejection of the needle and medicament.

Other objects will become apparent from a consideration of the followingspecification and claims when taken in conjunction with the accompanyingdrawings in which:

FIG. 1 is a cross-sectional view of an improved hypodermic injector, thespring thereof being shown in released position and the injectorincorporating the detent means of this invention;

FIG. 2 is a plan view of one form of detent forming part of theinvention;

FIG. 3 is a plan view of a second form of detent forming part of theinvention; and,

FIG. 4 is a diagrammatic view illustrating the position of parts withthe detent, such as the flat detent of FIG. 2, partially operated forrelease of the spring.

Reference is made to the disclosure in the Sarnoff et a1. patent forsuch structure and mode of operation of the syringe as is not whollydisclosed herein.

Referring to the drawings herein and adverting particularly to FIG. 1,it will be noted that the vial holder structure herein may be made verysimilar to that shown in the Sarnoff et al. patent previously referredto, though the precise structure of vial holder therein is not theessence of the invention; any form of holder for vial and spring issuitable, so long as a shoulder is provided for detent engagement. Themain difference, it will be noted, is in the configuration of a detentshaft and its action.

As a specific embodiment of the invention, FIG. 1 discloses in crosssection and in released condition of the spring, an outer sleeve orsheath of plastic or metal open at the lefthand end and closed, exceptfor a perforation 12, at the righthand end 14. Telescopingly mounted inthe outer sleeve is a tube 16, also of plastic or metal, secured in anyconvenient manner to a metallic spring housing 18, open at the lefthandend 20 and closed by a collar 21 at the righthand end, except for aperforation 22, for the passage therethrough of a detent portion of thenovel shaft to be described. The tube 16 is closed at the lefthand end,except for a perforation 24, to permit extrusion of the needle 26.

Within the lefthand end of the tube 16 is a vial 28, shown in FIG. 1 asemptied of its contents, the vial being provided with a rubber stopper30, penetrated by the hollow needle, the needle having been driventhrough the rubber stopper and the contents of the vial having beenejected through a passageway in the needle by reason of a piston 32within the vial having been driven to the left. The drive of piston 32was effected by displacement of disc member 34, the disc being driven bythe spring seat end 36 of a shaft 38, shaft 38 being driven in turn byreason of release of compression of a helical spring 40. The springreacted between the spring seat on the shaft and the inside face ofcollar 21. The shaft, as shown. in FIG. 2, is provided near its endopposite the spring seat with a detent portion indicated generally as 42in FIG. 2. The shaft 38 is cylindrical; the seat 36 is a circular flangeand the detent end of the shaft is provided with a conical portion 44and a slotted portion 46 extending completely through the shaft, theslot in the shaft extending but a short distance above the cone and amuch longer distance below the cone. The cone has its conical portion 44diverging away from the axis of the shaft in the direction of the seatand thereis a surface 50' extending outwardly from the shaft. Thissurface is normally parallel to and engages the upper surface of thecollar 21 when the spring is under compression and the device cocked foroperation. Also in cocked position and integral hollow bridging neckportion 52 of the shaft may extend thru aperture 12 in the outer sleeveto receive a locking pin (not shown) inserted into the device to preventinadvertent unseating of the detent and release of the needle andmedicament.

By reason of the slotted construction of the shaft and integral neck 52,however, undesired sliding of the detent surface 50 from oh? the collar21 is made difficult as will become apparent. With the construction ofthe prior art, as in the Sarnoff et a1. patent previously referred to,pivoting of the arms supporting the detent portion occurs at the closedend of the slot. As a consequence any forces, as inertia forces,incurred when dropping the hypodermic device when the safety pin hasbeen removed, which tends to slightly move the arms toward each other,angles the detent surface which engages the collar to present an acuteangle between it and the collar surface, promoting sliding action of thedetent surface in a direction to cause release of the shaft.

By reason of the closed at both ends slotted construction disclosedherein, when an unintended force tends to move the detent surface,because of the two pivots provided by the ends of the slot in the shaftand the shortness of the portion of the slot above the surface 50compared to the remaining ortion of the slot, the surface 50 angles inan opposite direction to that which occurs in the prior art. Therefore,as seen diagrammatically in FIG. 4, the springiness in the material ofthe shaft and the angularity of the surface is such as to tend torestore the detent to locked position.

Normal release of parts is effected by telescoping action of the outersleeve with respect to the holder for the vial, whereupon the wallsurrounding the perforation 12 engages the conical surface portions ofthe detent and forces them together sufliciently to allow the detent topass through the opening 22, the slotted portion permitting suflicientflexing of the walls of the shaft to take place to permit this action.

In the modified form of invention shown in FIG. 3, instead of the shaftand seat being cylindrical, the same maye be made of a flat bar, as bar54, rectangular in cross section, thereby saving material. The neck orbridge piece 56 is hollow and cylindrical to permit insertion of thelocking pin referred to hereinabove. When no safety pin is employed, theentire shaft, including the bridge piece at the end of the slottedportion, may be fiat.

Having thus described the invention, what is claimed is:

1. A spring propelled control element for a hypodermic injectorcomprising a shaft of resilient material, a spring seat at one end ofthe shaft, a detent adjacent to but removed from the other end of theshaft, said detent having a sloping surface diverging in a directiontoward the spring seat and a second surface intersecting the firstsurface and extending laterally from the shaft, said shaft being slottedlongitudinally of the shaft from a point close to but not at said oneend of the shaft and closer to said one end than the second surface, toa second point along the shaft beyond said second surface, said slottedportion of the shaft from the second intersecting surface level to thesecond point being longer than the remainder of the s'otted portion.

2. A spring propelled control element for a hypodermic injectorcomprising a shaft of resilient material, a spring seat at one end ofthe shaft, a slotted portion in the shaft extending from adjacent oneend of the shaft but removed from the end thereof and extending towardthe spring seat, a detent on the shaft adjacent to said one end of theshaft and positioned intermediate the length of the slotted portion,said detent comprising a surface sloping divergently in the direction ofthe spring seat end of the shaft and a second surface intersecting thefirst surface and extending laterally from the shaft, the slottedportion between the second surface and the seat end of the shaft beinglonger than the remaining portion.

3. The structure of claim 1 wherein the shaft is a fiat member and thereis provided a second detent, the detents being at the same level alongthe length of the shaft and extending from the shaft on opposite side ofthe flat member.

4. The structure of claim 1 wherein the shaft is a cylindrical member,and the portion of the shaft on the one end thereof is constituted of acollar integral with the portions of the shaft on each side of theslotted portion thereof.

5. The structure of claim 4 wherein the detent is in the form of afrustum of a cone with the slotted portion passing through the frustumof the cone.

6. The structure of claim 1 wherein the material is a plastic.

7. The structure of claim 1 wherein the material is metallic.

8. In a hypodermic syringe device, a vial for fluidhaving a puncturablesealed opening, a hypodermic needle withdrawn therein in alignment withsuch sealed opening, a piston within said vial, said needle beingdrivably secured to said piston and drivable through such sealed openingin response to pressure acting upon said piston,

a holder for said vial, said holder mounting a driving spring positionedfor urging said piston outwardly, and means for releasably holding saiddriving spring in a compressed condition, saidmeans comprising a shaftof resilient material, a seat seating said driving spring at one end ofthe shaft, a detent on said shaft close to the other end of the shaftand engageable with but releasable from a portion carried by the holder,said detent having a sloping surface diverging in a direction toward thespring seat and a second surface intersecting the first surface andextending laterally from the shaft, said shaft being slottedlongitudinally of the shaft from a point close to but not at said oneend of the shaft, and closer to said one end than the second surface, toa second point along the shaft beyond said second surface, said slottedportion of the shaft from the second intersecting surface level to thesecond point being longer than the remainder of the slotted portion, andmeans engaging the sloping surface to move it toward the axis of theshaft to unseat the detent and release the spring from compression.

References Cited UNITED STATES PATENTS 2,832,339 4/1958 Sarnoff et a1.128-218 2,871,856 2/1959 Stiener 128216 3,320,955 5/1967 Sarnoff 128218FOREIGN PATENTS 955,180 1/1950 France.

RICHARD A. GAUDET, Primary Examiner.

D. L. BAKER, Assistant Examiner.

2. A SPRING PROPELLED CONTROL ELEMENT FOR A HYPODERMIC INJECTORCOMPRISING A SHAFT OF RESILIENT MATERIAL, A SPRING SEAT AT ONE END OFTHE SHAFT, A SLOTTED PORTION IN THE SHAFT EXTENDING FROM ADJACENT ONEEND OF THE SHAFT BUT REMOVED FROM THE END THEREOF AND EXTENDING TOWARDTHE SPRING SEAT, A DETENT ON THE SHAFT ADJACENT TO SAID ONE END OF THESHAFT AND POSITIONED INTERMEDIATE THE LENGTH OF THE SLOTTED PORTION,SAID DETENT COMPRISING A SURFACE SLOPING DIVERGENTLY IN THE DIRECTION OFTHE SPRING SEAT END OF THE SHAFT AND A SECOND SURFACE INTERSECTING THEFIRST SURFACE AND EXTENDING LATERALLY FROM THE SHAFT, THE SLOTTEDPORTION BETWEEN THE SECOND SURFACE AND THE SEAT END OF THE SHAFT BEINGLONGER THAN THE REMAINING PORTION.